"'coroutine' object is not callable" in python asyncio WebSocket client

Question

Currently, I am producing a WebSocket client in python using asyncio that connects to a server every second until I interrupt it with my keyboard and outputs the response from the server to a .csv file. When I run the script, It successfully runs, but I get this in my terminal:

'coroutine' object is not callable

When I press Ctrl + c to abort the code, I get the following:

sys:1: RuntimeWarning: coroutine 'test' was never awaited

What is the issue here and how do I resolve it? Mypython code is given below:

import asyncio
import websockets
import logging
import datetime
import time

starttime = time.time() # start value for timed data acquisition

logger = logging.getLogger('websockets')
logger.setLevel(logging.INFO)  #Switch to DEBUG for full error information
logger.addHandler(logging.StreamHandler())

class Timer: #class for asynchronous (non-blocking) counter
    def __init__(self, interval, first_immediately, callback):
        self._interval = interval
        self._first_immediately = first_immediately
        self._callback = callback
        self._is_first_call = True
        self._ok = True
        self._task = asyncio.ensure_future(self._job())
        print("init timer done")
    async def _job(self):
        try:
            while self._ok:
                if not self._is_first_call or not self._first_immediately:
                    await asyncio.sleep(self._interval)
                await self._callback(self)
                self._is_first_call = False
        except Exception as ex:
            print(ex)
    def cancel(self):
        self._ok = False
        self._task.cancel()


async def test():
    async with websockets.connect("ws://198.162.1.177:80/", ping_interval=None) as websocket:

        await websocket.send(str(1.001))  #send a message to the websocket server
        response = await websocket.recv() #wait to get a response from the server
        print(response)
        dataline_pv1 = datetime.datetime.today().isoformat() + "," + str(response) + "," + str(0) + "\n" # format and assemble data line
        file_name_pv1 = '{:%Y%m%d}'.format(datetime.datetime.today()) + "_flow.csv" # generate file name

        with open(file_name_pv1, "a") as etherm_file1: # append dataline to file
            etherm_file1.write(dataline_pv1)
            
        
#asyncio.get_event_loop().run_forever(test()) # run until test() is finished while True:
timer = Timer(interval=1, first_immediately=True, callback=test())

loop = asyncio.get_event_loop()
try:
    asyncio.ensure_future(test())
    loop.run_forever()
except KeyboardInterrupt:
    timer.cancel()
    pass
finally:
    print("Closing Loop")
    loop.close()

Feuermann · Accepted Answer · 2021-07-14 13:40:11Z

1

You have error in your Timer initialization. You places coroutine object, but you need callable function instead.

Change initialization from

timer = Timer(interval=1, first_immediately=True, callback=test())

to

timer = Timer(interval=1, first_immediately=True, callback=test)

answered Jul 14, 2021 at 13:40

Feuermann

3443 silver badges7 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Ryan Schaefer · Accepted Answer · 2021-07-14 13:48:25Z

1

It seems like you are calling test rather than passing the coroutine test in places where you expecting a value. The result of test() (calling test) is a coroutine object that is never awaited. Therefore, you should treat test like a value rather than a function which you are calling.

Relevant lines to look at:

timer = Timer(interval=1, first_immediately=True, callback=test)
#                                                             ^

edited Jul 14, 2021 at 13:48

answered Jul 14, 2021 at 13:34

Ryan Schaefer

3,1101 gold badge29 silver badges48 bronze badges

2 Comments

Feuermann Over a year ago

ensure_future requires Corouitine or Future, not 'function'.

tjsmert44 Over a year ago

so the line asyncio.ensure_future(test()) should then be changed to asyncio.ensure_future(test) too?

Oyono · Accepted Answer · 2021-07-14 14:15:13Z

0

You should pass test instead of test() to callback kwarg otherwise, test() returns a coroutine object that is never awaited (thus the RuntimeWarning you are getting at the Timer(interval=1, first_immediately=True, callback=test()) line and the 'coroutine' object is not callable error you are getting due to the await self._callback(self) line)

edited Jul 14, 2021 at 14:15

answered Jul 14, 2021 at 13:42

Oyono

3671 silver badge8 bronze badges

Collectives™ on Stack Overflow

"'coroutine' object is not callable" in python asyncio WebSocket client

3 Answers 3

Comments

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related